The dielectric barrier discharge is of current interest in the technical community as a result of its potential for use in surface modification applications as well as for service in environmental cleansing applications ranging for example from engine exhaust to sludge remediation. Of particular attraction in modern applications is the possible use of dielectric barrier discharge devices operating at ambient pressures rather than under the vacuum conditions often required for discharge phenomenon devices. A variety of energization and triggering arrangements for these dielectric barrier discharge devices have become known in the art, these arrangements usually involve a high voltage energy source supplemented by an additional source of triggering or discharge-initiating signal. Many of these energization arrangements are however so complex as to discourage use of the dielectric barrier discharge concept in simple low cost apparatus. The present invention is believed to provide assistance in resolving these difficulties.
The present invention provides an improved and simplified arrangement for energization of a dielectric barrier discharge device or similar device.
It is an object of the invention therefore to provide a simplified and electrically convenient circuit arrangement for energizing a dielectric barrier discharge device.
It is another object of the invention to provide enhanced understanding of the electrical operating characteristics of a plasma discharge apparatus such as a dielectric barrier discharge device.
It is another object of the invention to achieve the low gas temperature and high electron temperature advantages of dielectric barrier discharge device plasmas using a simplified energization arrangement for obtaining these plasmas.
It is another object of the invention to achieve energization of dielectric barrier discharge devices and similar devices in a manner offering improved safety and convenience for persons associated with the devices.
It is another object of the invention to provide a reliable dielectric barrier discharge device energization arrangement that is electronic in nature and can be achieved without moving parts.
It is another object of the invention to achieve the known advantages of high frequency energization of a dielectric barrier discharge device while avoiding the complexity and cost of conventional arrangements to accomplish such energization.
It is another object of the invention to provide a dielectric barrier discharge device energization arrangement that may be used with a plurality of differing types of electrical energy sources.
It is another object of the invention to provide a dielectric barrier discharge device energization arrangement seizing upon the advantages available with use of an impulse energized low inductance electrical circuit.
It is another object of the invention to provide a dielectric barrier discharge device energization arrangement in which either resistive or reactive decoupling may be used between energy source and low inductance portions of the apparatus.
It is another object of the invention to provide a dielectric barrier discharge device energization arrangement in which substantial parts of the apparatus can be permanently and safely operated at ground potential.
These and other objects of the invention will become apparent as the description of the representative embodiments proceeds.
These and other objects of the invention are achieved by the method of controlling plasma discharges in a gaseous dielectric barrier discharge device, said method comprising the steps of:
applying electrical charging energy to electrical terminals of a capacitance element comprised of electrically segregated conductive electrodes of said gaseous dielectric barrier discharge device;
said step of applying electrical charging energy comprising an electrical charging current flow of controlled first current amplitude and first capacitance charge-changing rate;
said step of applying electrical charging energy continuing until said electrical capacitance element achieves a charge voltage intermediate a minimum and a maximum dielectric barrier discharge initiating voltage characteristic of said gaseous dielectric barrier discharge device;
initiating a dielectric barrier discharge within said charged capacitance gaseous dielectric barrier discharge device by decreasing said achieved charge voltage at said capacitance element electrical terminals at a second, substantially faster capacitance charge-changing rate.